[Tfug] Disk editing

[Bexley Hall]

Hi,

I've got an oddball piece of kit with a disk in it.
The disk doesn't use a "recognized" partition table.
I want to edit the partition table but can't use
any traditional partition editors as the format of
the partition table is so bogus.

So, I need to just be able to patch a sector on the
drive.

Any suggestions as to how I can reliably do this?
Note that I can't write anything to the disk (other
than the sector in question) as the filesystem on
the disk is incomprehensible to anything other than
the device itself!

My first guess is to dd(1) the first sector onto a
floppy (I think I can coax the device into letting me
do this).  Then, edit the image on the floppy and
dd(1) it back onto the raw drive.

This is obviously a kludge but I *think* it is a
safe approach?